Dr. Edgar J. Sintema received his Ph.D. cum laude in mathematics education at the University of Valladolid, Spain, under the Supervision of Prof. José María Marbán. He had previously earned an MSc in mathematics education at Copperbelt University, Zambia. His dissertation research focused on the subject matter and pedagogical knowledge of pre-service mathematics teachers in relation to the concept of a function, a fundamental concept in mathematics. His research interests are in developing new strategies for the implementation of existing and new problem-solving models with the aim of supporting and shaping the teaching and learning of mathematics. He is also interested in researching the use of technology in teaching mathematics.